Baroreflex Activation Therapy Lowers Blood Pressure in Patients With Resistant Hypertension - Rheos Pivotal Trial


The goal of the trial was to evaluate carotid baroreceptor stimulation compared with no carotid baroreceptor stimulation among patients with resistant hypertension.


Carotid baroreceptor stimulation will be safe and effective for the treatment of resistant hypertension.

Study Design

  • Randomized
  • Blinded
  • Parallel

Patient Populations:

  • Patients with systolic blood pressure ≥160 mm Hg, diastolic blood pressure ≥80 mm Hg, or 24-hour average ambulatory blood pressure ≥135 mm Hg treated for at least 1 month with three antihypertensive medications at maximum doses

    Number of enrollees: 265
    Duration of follow-up: mean, 21 months
    Mean patient age: 54 years
    Percentage female: 36%

Primary Endpoints:

  • Co-primary endpoints (all components had to be met to demonstrate overall efficacy and safety):
    • Short-term acute response
    • Long-term sustained response
    • Procedural safety
    • Baroreflex stimulation therapy safety
    • Device adverse events

    Drug/Procedures Used:

    Patients with resistant hypertension and who agreed to have a pulse generator (Rheos System, CVRx, Inc., Minneapolis, MN) implanted to each carotid sinus for carotid baroreceptor stimulation were randomized to group A: the device turned on from months 0-12 (n = 181) versus group B: device turned off for 6 months, then turned on from months 6-12 (n = 84).

    Concomitant Medications:

    At baseline, the following medications were used: diuretics in 96%, beta-blockers in 86%, calcium channel blockers in 65%, angiotensin-converting enzyme inhibitors in 57%, angiotensin-receptor blockers in 47%, alpha-blockers in 12%, and sympatholytic agents in 44%.

    Principal Findings:

    Overall, 265 patients were randomized. Among group A participants at baseline, the mean age was 54 years, 36% were women, 31% were diabetics, 14% had a prior stroke, the mean number of antihypertensive medications was 5.2, and the mean blood pressure was 169/101 mm Hg. The mean follow-up was 21 months.

    At 6 months, ≥10 mm Hg decrease in systolic blood pressure occurred in 54% of group A versus 46% of group B (p = 0.97). The mean decrease in systolic blood pressure was 16 ± 29 mm Hg in group A versus 9 ± 29 mm Hg in group B (p = 0.08).

    At 6 months, freedom from baroreflex stimulation adverse events was 92% in group A versus 89% in group B (p for noninferiority < 0.001).

    At 12 months, freedom from device-related adverse events was 87% in groups A and B combined.

    Among all patients at 30 days, 4.8% had permanent nerve injury, 4.4% had transient nerve injury, 4.8% had general surgical complications, and 2.6% had respiratory complaints.

    Secondary outcome at 6 months: ≤140 mm Hg systolic blood pressure occurred in 42% of group A versus 24% of group B (p = 0.005), and at 12 months, this outcome occurred in 53% of group A versus 51% of group B (p = 0.70).


    Among patients with treatment-resistant hypertension, the use of carotid baroreceptor stimulation represents a novel treatment approach. This therapy did not improve the proportion of patients who had a ≥10 mm Hg decrease in systolic blood pressure at 6 months, one of the five co-primary endpoints.

    However, in a secondary outcome, the proportion of patients who achieved ≤140 mm Hg systolic blood pressure at 6 months was greater with carotid stimulation. This procedure required general anesthesia and was associated with an increased risk of permanent nerve injury. By contrast, renal sympathetic denervation (Symplicity HTN-2) lowered systolic blood pressure by at least 10 mm Hg in 84% of patients versus 35% of control patients.


    Bisognano JD, Bakris G, Nadim MK, et al. Baroreflex Activation Therapy Lowers Blood Pressure in Patients With Resistant Hypertension: Results From the Double-Blind, Randomized, Placebo-Controlled Rheos Pivotal Trial. J Am Coll Cardiol 2011;Jul 28:[Epub ahead of print].

    Presented by Dr. John Bisognano at the ACC.11/i2 Summit, New Orleans, LA, April 5, 2011.

    Clinical Topics: Heart Failure and Cardiomyopathies, Prevention, Hypertension

    Keywords: Stroke, Pressoreceptors, Follow-Up Studies, Carotid Sinus, Sympathectomy, Baroreflex, Blood Pressure, Kidney, Hypertension, Diabetes Mellitus

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